On 2023-03-13 12:57 am, Jean Abou Samra wrote:
Le 13 mars 2023 à 06:24, Paul Scott <waterhorsemusic@aol.com> a écrit :
What I'm not sure about is what volta does. A function but what are
its arguments and what does it do?
Nope, since it’s quoted, it doesn’t get evaluated but remains a
symbol. See
https://scheme-book.readthedocs.io/en/latest/scheme/data-types/symbols.html
or https://extending-lilypond.gitlab.io/en/scheme/quoting.html
And as far as LilyPond is concerned, repeatCommands is a list of
either individual symbols like 'start-repeat or nested lists such as
(volta "1."). The symbol 'volta is used to indicate starting or
stopping a volta bracket. If the following value is a string or
markup, a volta bracket is created with the specified text. Otherwise
if the second value is false (#f), then this instructs LilyPond to
terminate the current volta bracket.
While Scheme shorthand is often very convenient, it can be helpful to
be able to translate between the verbose longhand form.
Consider:
'((volta #f) end-repeat (volta "2."))
Written out, this is equivalent to:
(list (list (quote volta) #f) (quote end-repeat) (list (quote volta)
"2."))